Rice Koji

Rice koji is made by sprinkling koji mold spores onto steamed rice and incubating for about 48 hours under controlled temperature and humidity. It has strong saccharification power, efficiently converting starch to sweetness.

In miso making, the proportion of rice koji (koji ratio) determines flavor direction — more koji means sweeter, less means saltier. Some fermented foods like amazake and shio-koji are made from rice koji alone. When white mycelium softly covers the rice, fermentation is ready to begin. Rice variety subtly affects sweetness and aroma. Start with readily available regular rice for your first attempt.